There are many emergency situations in which it is essential to rapidly and accurately place a endotracheal tube into a patient's trachea. Thus, for example, when a patient exhibits signs and symptoms of cardiopulmonary arrest, respiratory failure, airway obstruction, severe head injury, poisoning, and/or drug overdose, it is often critical to protect the patient's airway and/or to ventilate the patient's lungs as readily as possible. In many cases, death or severe injury often results from a failure to accurately and rapidly perform this procedure.
The endotracheal tube must be precisely positioned within the patient's airway; it should be neither too high nor too low in the trachea.
If the tube is not inserted far enough into the trachea, it can cause severe damage. In the first place, it might not protect against aspiration of the patient's stomach contents; such aspiration can choke the patient and cause his death. In the second place, it is more likely to be readily dislodged whe placed too high. In the third place, air delivered through the tube may flow, in part or whole, through the patient's mouth and/or nose and not adequately ventilate his lungs. In the fourth place, the misplaced tube might severely damage the patient's vocal cords.
If the endotracheal tube is inserted too far into the patient's trachea, it often causes other severe problems. As is indicated by a article by J. Adriani et al. entitled "Complications of Endotracheal Intubation" (Southern Medical Journal, Volume 81, No. 6, pages 739-744), the trachea bifurcates at the level of the second rib. If the endotracheal tube is inserted beyond this bifurcation point, only one lung will be ventilated by the tube, thereby often causing the other lung to collapse; and a failure to provide oxygen to both lungs may cause a potentially fatal oxygen deficit to occur. Furthermore, delivery of all of the volume of air to the one lung may damage that lung.
One means of insuring that the endotracheal tube has been properly inserted into a patient's trachea is to conduct a x-ray of the patent's chest. However, this is a rather time-consuming, expensive procedure which, in the case of malpositioning of the endotracheal tube, must be repeated until analysis indicates proper placement. The luxury of conducting repeated chest x-rays is often not available in life-and-death situations in which it is essential to properly and speedily place the endotracheal tube. Ambulances, for example, do not contain portable x-ray machines.
The prior art has attempted to provide inexpensive, accurate means of placing a endotracheal tube within a patient's trachea; such attempts have only met with limited success.
In an article by Gabriel Hauser et al., entitled "Prospective evaluation of a nonradiographic device for determination of endotracheal tube position in children," Critical Care Medicine, Volume 18, No. 7 (1990), at pages 760-763, a discussion of the "TRACH-MATE" intubation system is presented; this system is sold by McCormick Laboratories of North Chelmsford, Mass. As is indicated in this article (at page 760), this device ". . . consists of a sterile, single-use, polyvinyl chloride ETT [endotracheal tube] which contains a magnetically detectable metallic element within the tube wall at a defined distance from the distal tip of the tube . . . . A portable, battery-powered locator instrument has a 1.3-cm diameter pointer probe, and is capable of detecting the marker transcutaneously. The instrument operates by detecting the change of the alternating magnetic field emitted by the probe when the field is perturbed by the presence of the metallic interference element embedded in the ETT wall."
The prior art has recognized certain limitations in the use of the "TRACH-MATE" system. Thus, in an article by Arthur Engler entitled "Verifying Endotracheal Tube Placement With the TRACH MATE . . . Intubation System," appearing in Pediatric Nursing, July-August, 1989, Volume 15, No. 4 (at pages 390-392), it is disclosed that: "Use of the TRACH MATE . . . endotracheal tube is contraindicated in cases in which the infant has metallic or magnetic objects or devices located near the trachea . . . . Special care should be used when magnetic resonance imaging . . . scans are needed on patients with the TRACH-MATE endotracheal tube in place. Image distortion of anatomical locations near the tube's magnetic marker in the trachea may occur." (at page 391)
Even when the "TRACH-MATE" system is used in situations where it is indicated, the results obtained have been disappointing. As reported in the aforementioned article appearing in Critical Care Medicine, Hauser and his colleagues conducted several studies with the "TRACH-MATE" system. In one study of twenty children, summarized in Table 2 (at page 762), ten of the twenty placements of the endotracheal tube with the "TRACH-MATE" system were incorrect: eight were too high, and two were too low.
In addition to the high-failure rate reported by Hauser et al. for the "TRACH-MATE" system, other problems are presented by this system. In the first place, it requires the use of a special endotracheal tube which contains metallic material embedded on its inside surface; this special tube is not widely available or widely used, and it is not believed to be available in sizes suitable for use in adults. In the second place, it is rather expensive, costing in excess of five-hundred dollars for the locator instrument used in the system. In the third place, it requires at least two operators to properly use during intubation; one of the operators must hold the laryngoscope (which is used to visualize the vocal cords) while inserting the endotracheal tube, while another operator must hold the locator in place on the patient's chest. In the fourth place, the device should not be used when any metallic objects are near the patient's trachea. In the fifth place, the special endotracheal tube required (which costs in excess of $7.00) is not reusable.
It is a object of this invention to provide an apparatus for rapidly and properly positioning an endotracheal tube within a patient's trachea whose use will result in a substantially higher percentage of proper positionings than the prior art systems.
It is another object of this invention to provide an apparatus for properly positioning an endotracheal tube within a patient's trachea which is both reusable and relatively inexpensive.
It is another object of this invention to provide an apparatus for properly positioning an endotracheal tube within a patient's trachea which can be used with conventional, inexpensive, readily available endotracheal tubes.
It is another object of this invention to provide an apparatus for properly positioning an endotracheal tube within a patient's trachea which, while the endotracheal tube is being positioned, allows the patient to be ventilated.
It is yet another object of this invention to provide an apparatus for checking the placement of endotracheal tubes which have bee positioned in a patient by other means.